Sight correcting device for weapons



June 24, 1941. 'E. LANCIANI 2,246,632

SIGHT' CORRECTING DEVICE FOR WEAPONS Filed F913. 25, 1939 2 Sheets-Sheet 1 III VELOCITY INVENTOIZ:

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33 GEOMETRICAL \NSTRUMILNIE.

June 24, 1941,

E. LANCIANI SIGHT CORRECTING DEVICE FOR WEAPONS Filed Feb 23, 1939 2 Sheets-sheet 2 INVENTOR, BY EJ117041 mum ATTORNEYS.

33'. GEONlETRlCAL lN'STRUMENlS.

Patented June 24, 1941 eienitili SIGHT CORRECTING DEVICE FOR WEAPONS Ettore Lanciani, Milan, Italy, assignor of onehalf to I. S. 'S. A. Industria Specializzata Strumenti Aeronavigazione, Societa Anonima,

Ponte S. Pietro, Italy Application February 23, 1939, Serial No. 257,864 In Italy March 1, 1938 2 Claims.

The present invention refers to a sight-correcting device for weapons placed on board of vehicles, and especially on aircraft.

When from on board of a moving vehicle and particularly from aircraft, the weapon is aimed at a moving target, it is not possible to use the natural line of sight.

In order to hit the target, it is necessary to have a corrected sight-line, taking into account the relative speed of the vehicle and of the target. The velocity of the firing vehicle coordinates with the projectiles velocity, so that the actual trajectory is deviated relatively to the natural line of sight.

Besides, the target having a certain velocity and the projectile requiring a certain time to cover the distance between the shooter and the target, it is essential, in order to hit the target, that the actual trajectory of the projectile be directed at the point where the target in consequence of its movement will be at the end of said time. Therefore in conclusion in order to aim properly, it is required to make use of a sight corrector which takes into account the velocities of both shooter and target and in relation thereto, the correcting device should bring about the proper corrections, in order that the line of sight should be the best adapted to hit the target.

The device according to the invention is characterized substantially by the feature, that it contains conjugated sighting members associated with the weapon, and reciprocally shiftable, so that the line of sight provided bythem, may form an angle varying with the centre-line of the weapon, in dependance upon the component of the vehicles normal velocity, which is at right angles to the trajectory of the projectile, the change of said angle being brought about in an interdependent way from the angular displacement of the weapon itself in relation to the vehicle, preferably through a positive gear motion by swinging two arms of equal length, being preferably adjustable, maintained parallel, and carrying an articulated crossbar providing one element of the sight, the other element being in fixed relation with the weapon.

The invention provides a particular structure for this second element of sight, embodying means for correcting the fire in relation with the velocity of the target.

The invention will now be disclosed with reference to the attached drawing, given as an example of an embodiment and limiting in no way the invention.

Figures 1 and 2 are two diagrammatic views, respectively in top view and in side view of a weapon provided with the present sight-correcting device;

Fig. 3 shows in vertical axial section the mechanism carrying the moving rearsight-notch;

Fig. 4 is a top view of the said mechanism; and

Fig. 5 shows the constructional design of the sight with the target velocity corrector.

In Figs. 1 and 2, A is the weapon, B the sight line correcting device, C the sight, with the targets velocity corrector. The sight-notch l2 can move on a circle, so as to obtain a series or star X of corrected sight lines having their centre in sight 3:.

The corrector B of the speed of the shooter (see also Figs. 4 and 3) consists in a box I, forming the support for three pins 2, 3 and 4, cinematically connected to each other by means of gear wheels 5, 6 and 'I, so that the motion impressed by shaft 8, due to the angular deflections of the weapon, is transmitted through the pair of hellcoidal gears-8 and through gearwheels 5, 6 and 'l, to cranks or arms 9 and H], the extremity of which carries a link ll carrying the backsight l2, adjustments being possible by means of the shiftable pivots 9 and I0.

Therefore, due to the angular displacement of drive shaft or arbor 8, the backsight I2 moves on a circle D, whose radius depends on the length of cranks 9 and lo, and which is adjustable according to a conventional scale in relation to the values of the velocity of the carrying craft.

Said corrector B is arranged in such a way that the plane containing the centre-line I3 of the grip-handles of the weapon, coincides with the plane of the circle D traced by the backsight l2, and also that the centre 0 of this circle falls on said centre-line 13. Thus, if foresight I5 is fixed at a certain distance d from the centreline of the grip-handles, which represents in scale the initial velocity of the projectile; the line drawn from backsight l2 through the natural foresight l5, gives the desired sightline corrected for the velocity of the shooter.

Corrector C for the velocity of the target (see also Fig. 5) is a mixed polygonal structure, formed by two arched sides l6 and I1, concentric with natural sight I5, and by two straight sides 3 and Hi.

In order to get a good aim, the weapon will be placed in such a way that sight line I2l5 cuts the trajectory of the target; the volley being started at the moment the target comes very such a manner that the line of sight determined by the position of the two sights shall form with the centerline or axis of the gun an angle which is caused to vary in correspondence with or proportional to the travel speed of the craft or its component which is at right angles to the corrected trajectory of the projectile; the change or adjustment of said angle being determined and brought about in a manner which is dependent upon the angular displacement of the gun relatively to the fore-and-aft axis of the craft. This adjustment and swing are preferably brought about by means of gear wheels, such as illustrated, acting upon the equal and parallel arms 9 and It! to swing the arms in parallelism and thereby, through the articulated crossbar ll, adjusting the position of the sight [2 in a circular path while the other sight remains in fixed relation to the gun. Two initial factors in these operations are the previously known velocity of the projectile and the speed of travel of the craft, and the described device is readily adjustable to any predetermined craft speed by adjusting the lengths of the two carriers or arms 9 and to determine the radius of the adjustment movements of the sight 12.

The sight mechanism B or l2 in its movements describes a series of vectors or angular direction lines the plane of which contains the center line [3 of the grip handles of the gun; each such vector or line being set or directed by a train of gear wheels, such as 5 to 8, parallel to and in opposite direction to the direction of the motion. This vector or direction line has a length which maybe initially varied or adjusted in accordance with the speed of travel of the craft.

These described corrections are for the speed of the craft itself at various directions relative to the sight line between craft and target. To allow for the speed of the target, if it be in travel, the invention includes the correcting means described as embodied in the front or fixed sight C or IE, which for the purpose is in the form of an open polygon or four-sided figure, two opposite sides of which are arcs of circles, making convenient the allowance for the target's speed,

These sights are relatively shiftable, as

the other sides being preferably straight. This front sight correcting means is mounted to remain at a fixed distance from the axis about which the gun and grip handles swing irrespective of the speed of the craft and of the adjustments due thereto.

It is to be understood that the parallel swinging arms 9 and H] are operated to remain constantly parallel to the longitudinal axis of the craft as the gun is swung in train.

It should be understood that the details of constructions and of application of the object of the invention, may vary in any way, without exceeding the limits of the invention and therefore of the protection of the patent.

What I claim and desire to secure by United States Letters Patent is:

1. A sighting mechanism for a firing weapon adapted to be mounted an d gpe rated upon amovable vehicle, comprising, in cofilfi'ination, a first "an "second longitudinally spaced cooperating sights, the first sight being fixed in relation to the weapon, a parallel motion device comprising a pair of swingable parallel arms of equal length and a link pivotally interconnecting said arms, on which link the second of said sights is mounted, whereby said parallel arms are swingable in unison to cause the second sight to revolve in the arc of a circle relatively to the weapon, gear mechanism operated by the angular swing of the weapon in train with respect to the fore-and-aft axis of the vehicle to revolve said parallel arms according to the extent of such angular swing of the weapon to maintain them at all times parallel to the fore-and-aft axis of the vehicle, and means for adjusting the position of said link along said parallel arms to compensate for changes in vehicle speed.

2. A sighting mechanism for a firing weapon adapted to be mounted and operated upon a moving vehicle, comprising, in combination, a pair of longitudinally spaced cooperating sights, the first sight being mounted on the weapon, a parallel motion device comprising a pair of parallel arms of equal length and a link pivotally interconnecting said arms, on which link the second of said sights is mounted, said parallel arms being swingable in unison to cause the second sight to revolve in the arc of a circle relatively to the weapon about an axis that stands substantially perpendicularly to a line extending substantially parallel with the center line of the weapon and in which line the other sight is located, and gear mechanism operated by the angular swing of the weapon in train with respect to the longitudinal axis of the vehicle to swing said parallel arms to maintain them parallel to the axis of the vehicle.

ETTORE LANCIANI. 

